Resin bottles, representative examples of which are oriented polypropylene (OPP) bottles and polyethylene naphthalate (PET) bottles, are used for a variety of purposes, from beverages to food products and cosmetics. Such bottles are generally formed by using a blow molding device to perform two-axis stretching blow molding on resin preform that has been formed in a bottomed cylindrical shape by injection molding or the like.
A known blow molding device uses pressurized liquid instead of pressurized air as the pressurized fluid with which the preform is formed. In this case, if the content liquid that is ultimately filled into the product, such as a drink, cosmetic, medicine, or the like, is used as the liquid, then this approach allows the step of filling the content liquid into the bottle to be omitted and thus simplifies the production process.
When removing the bottle filled with content liquid from the mold of the blow molding device and transferring the bottle to the downstream process, the content liquid may spill from the bottle due to the effect of vibration, a change in velocity, or the like when the bottle is displaced, causing problems such as insufficient content liquid in the bottle or soiling of the bottle.
As a technique for resolving these problems, for example JP 2011-527244 A discloses a device that includes ducts 140, 145 and spouts 148, 149 for injecting liquid into a preform 110, a mold 100 having formed therein a cavity that molds the preform 110 into a predetermined bottle shape by injection of the liquid, a stretching rod 130 that stretches the preform 110, and a stoppering device that fixes and holds the cap against the bottle that has the liquid injected therein.
With the device in JP 2011-527244 A, however, it is necessary to remove the stoppering device 240 and position the stretching rod 130 directly above the preform 110 when molding the bottle, and to remove the stretching rod 130 and position the stoppering device 240 directly above the bottle when attaching the cap to the bottle. In other words, so that the stretching rod 130 and the stoppering device 240 do not interfere with each other, both need to be displaceable with respect to the mold, which complicates the structure of the device and leads to an increase in size of the device.
Therefore, as a device that blow molds preform using a liquid, it would be helpful to provide a new blow molding device that, while having a function to seal a bottle with a cap, has a simpler structure than a conventional device that includes a stoppering device.